Method of burning fuel in jetoperated rotor blades



4 Slfxeeizs-Sheer l w. BRzozowsKl lMETHOD oF BURNING FUL. INJET-OPERATED RQTpR BLADES May 19, '1953* Original Filed Nolv.-28v, 1945INVENTOR Nm Q3 BY May 19, 1953 w. BRzozowsKl 2,638,989

METHOD v0E BURNING FUEL 1N JET-OPERATED RoToR BLADES origial Filed Nov.28, 1945 4 sheets-sheet 2 May 19,1953 E w. B'RzozowsKl *n 2,638,989

METHOD OF BURNING FUEL IN JET-OPERATED ROTR BLADES Original Filed Nov.28; 1945 4 Sheets-Sheet 3 ATTORNEYS w. BRz'bzowsKl 2,638,989

OEERATED RoToR BLADES May 19, 1953 METHOD .0E BURNING FUEL 1N JEToriginal Filed Nov; 28', 1945 4 Sheets-Sheet INVENTOR ATTORNEYS PatentedMay 19, 1953 38,989 Y, mnonorommoruamnrarrorammo'norron sumas WitnldBrmnwski, Westmount,ltiimtreahQllihesz, Canada assiomi' 'to Stefan.zarnekijwalem l.oi-afinar appiiemm .November 28.. 1915 63131-9. mvideddams application nu .aw-23 ma., .semi No. 116.11mY

This application .is Aa division @f S. 631,319, .filed .November 28,1945, which matured .as Patent. No. 2,6QL258'.

`This :invention v.relates to aircraft..

Itis an objectfof .this 'invention` toaroyidean improved aircraft .that.hase-its ,power system com-- bined with .auxiliary means .torpmsmel-I-xg the additional power .required .for take fo, and .in the.case of .a helicoptel. for "xertcal hght. .In the preferred embedimentlof: the )invention =a helicopter .a Jetpropelled irtl?, landithe @adeditional power lfor takeoff. and rerticaiiiight is .obtained Joy.burn-ing '.fuelsvthin .the conduits, through which ..comp11essedairowszto the iet openings or nozzles. This auxiliary hea-tings a .less.efloient use :of the. fuel :than is ,obtained from an .internal.combustion engine .driving-.a compressor, hutitgprmlidesdsheEadd@@power'withl little `additional weight. and. @oostviai eguipment..

and since it, is used @only-or -fshort-mriodamhe operating .efoiency is-of Jess impntancethan.

the weight which would hefrequiiedzfor tliefasl-v ditionai .engine and.compressor @capacity that. would .he .needed to feet a boost in `power.reunaalent to that .obtained from the .use fof, .the aux-- iliaryheaters .of .this .invention @ne feature ofthe.finviemziohzmlatemtoahnner construction .for :heating aa, stream ifgasrwhie theeasvis :.tizaveiingqatsubstantial velocity. "The inventionutilizeszamuheplaceihnxsuch.imposition that a portionief theiar streamitramels.;through the` daube. A, Afuel sprayer .mathe umstream A.ond

of the ituhe .supplies 'ifuelethat' imixeswith :the

air and burns gas4 it ,howsmelone'the` length -ffoi the ftubie. Theytube :is .fhghlyfrheatedirto a. perature above the Aignitiontemperature sfroftime fuel, .and #the diameter .of thediube @unrelatedwith. :the mrstream @velocity f and' grate; fof rumepropagation-somtatheistream 'of xmlizand air is :burnedY.throughout.rits zentiremross.- sactionf'rhe foire reachingthe end.off-Lilie' tube.

@ther fnhjects, :features sand viaxhlantages @Wear or :be poi-mitad,rout. fas'- the; specification. proceeds.

Figure 11 isha-.iside y.geiev,ation fof' aheliuopten partky broken.zazwam zillustra'tixig.:the:manner in which `Aacompressed arri-iis'suppledeto fithef motor. and heatedzby-ffexhaustegasitrommheaengna rotorihub .and-.the .oonnectionsatornhplrmgarueir and compressed :air.ffromzitheuhuh 'tofsthe blades. w

Figure isa a. detail. wiew ksima/fing. .the wayin which lubricant issupplied to the centeybearings of .Figure 2,. x

`Figure .5 .a .-sectionaiylew .on the. 'linef'l--i of Figure 4. A

Figure .6 isan eniargedsectionai ,riem .online 6.5 of Figure i,`through'the nylon .ansixheat exchanger.

Eieure isy a .transverse .sectionaiyiewithroueh the-motor @blade shownmineure-51..

Compressed air from the housing A2,8 masses divides @and :passes@through enduits. 2.31 flefaflillfV toffthe .reispetiwesbladesofathestotorf-'lffhis-fheat.fexhaeeew3nprsesimetamesfselfolosedatmothaendsfhy @aus nies, limewire@to:theiwallslofnthe;wessels: ti;ff,'ape.21l

from the engine is-connected with an nletypjgpef at-vbheflowerfend'of@.thaheatexchangenbrandwereisrga .lgpp" 138' 01 he .hefirexchangerifmmwhichatne exhaust .sasaeseanes togtheatmosnhereifhisgcomtamtionparmi., the.

exhaustgasimmane.-eliemetognassfthro .the

tailmipeiaeatrtheirear me, withnanymf the. .o aovthrouehithewlonslradiatealieatft hansmitsehea .i .mandes there is .an .im

itoa'heamexchansr :.23

nd-intmtheln erhor ntelrimfatheipyionfandalso eii'rastreaman @kalorientaken of the full length of the pylon and a simple and lightweightheater used. .The apparatus 'shown is merely representative of heat`exchangers.

The internal construction'of 'thehub 3| is l shown in Figure 2. The hubincludes a nonrotatable or fixed portion 43 bolted to the upper end ofthe pylon 25, and a rotatable'portion 45. The rotatable iportion 45 isheld-down on the non-rotating member 43 by an attaching4 element 41which has a threaded center portion extending down and screwed into lanut 48. This attaching member 41 has threads 49 around its peripheraledge screwed into the rotatable hub member 45. f

. The nut 48 holds the inner race of a combined axial and thrustbearing- 50 against a shoulder of the attaching member 41, and a bearinghousing 52, which iit's over the bearing 5|), holds the outer race ofthe bearing 50 against'a spacer 53 which in turn bears against the outerrace of an alignment bearing 55. The innere-*race of this alignmentbearing 55 ts over the nut 48.

The bearing housing 52 has its lower end connected to a longitudinalcontrol yoke 51 by screws 56. The yoke51 is v'mounted on=a pin `58 withspacers 59 and't'll.``v This pin extends from both sides of a lateralcontrol axle 63, and the lateral control axle 63is'pivotally'attached-'to the fixed portion 43 of the rotor hub byaxle'pins 65 (Figure 4) held in place by covers 66. The ends of the axleB3 are streamlined, as shown in Figure 5,

so as to reduce the resistance that they offer to the upward passage'ofcompressed air from thepylon. The helicopter is controlled laterally bymeans'of lateral control cables 61 (Figure 2)-, and longitudinally by*means of longitudinal control cables 69 (Figure 4). The mating surfaceof the rotatable -hub .portion 45 over the iixed hub p0rtion 43 issubstantially spherical about a center at which the axis ofthe pin 58intersects the axis of the pins 65,'fand the rotatable hubportion 45rcanbe'tilted in'any' direction by means of the control cables 61 and'69. The rotor can, therefore, be tilted lforwardly so that the aircraftwill be propelled'forwardly without the use of an airscrew, making 4theaircraft, properlyspeaking, a

helicopter.

Rotation of the rotor is obtained by the reaction of jets of compressedair or gas expelled from :the blades or from some jet 'orifice or nozzleconnected to the blades.4 For purposes of the 'de-- scription andclaims; -the term blade in a broad sense to include not only the bladestructure proper but any' nozzles, pipes andother elements attachedtothe blade and-rotatable as a unit with it.

Compressed air that passes up through the pylon 25 enters the conduits31 which communicate with the interior of the rotor blades.` These theApylon 25 land Ebut "throughthev lconduitsr- 31?' to the rotor blades ofthe helicopter. Leakage between the xed portion 43 and rotatable portion45 of the rotor hub is reduced to a minimum by means of labyrinth glands11.

Figure 3 shows-'the wayin vwhich lubricant is supplied tothe bearing`50- and'other bearings incased beneath the connecting element 41. A

lubricant fitting 19 extending from the outside of thehub 3| leads to apassage 80 in the attachv,ingelernent ,41. `rI'his passage 8D has anoutlet 8| opening into the housing 52 above the bearing 50 lso -thatylubricant forced into the tting 19 passes through the passage 80 andfrom the outlet 8| drops 'down on the bearings within the housing 52.vLubricant is sealed in the housing 52 bya sealing ring, such as a feltwasher 8|,

retained in an annular groove in the top of the housing `53 and bearingagainst the underside 'of the'attaching element 41.

Figure 7 shows a section through one of the rotor blades 35. Theseblades are made of sections that include a leading edge section 84, acen-ter section and a trailing edge section 88. Compressed air iiowslengthwise in the blade 35 through the sections 84 and 85, both of whichserve as conduits for the compressed air, Near the outer edge of theblade 35 there is a jet opening or nozzle 89`through which compressedair from within the rotor blade ows rearwardly to develop the reactionwhich drives the blade forward. The nozzle 89 opens directly into thecenter section 85, but com-pressed air or gas from the leading edgesection84 flows into the center section at the region of the nozzle 89through an opening 9|. l

In the construction shown in Figure 8, the nozzle 89 is a separateelementfconnected to the center section of the rotor blade by fasteningssuch as rivets 93, and this -nozzle 89 has a restricted throat section94 and an expanding outlet for dis-' charging the gas or air athighvelocity. The jet orice or nozzle can be made as an integral part of thecenter section of the rotor blade, and

the blade can be made without the different sec-vv tions shown, andshaped to provide a suitable outlet for the gas. The term nozzle is usedin a broad sense, thereforeto indicate any jet opening `from which thecompressed gas can be dis-- burners comprising elongated tubes 91 and 98inl the sections 84 and 85 respectively. Each of these'tubes isconnected with a wall of the conduit by supporting-means |00 which holdthe tubes Bland 98 with their axes extending in the general direction ofthe flow of the gas stream and in such position that a portion of thegas stream in each of the sections 84 and 85 passes through the tube 91or 98 enclosed inthat section;-

These tubes 91 and-98 are in effect vby-pass conduits'through which aIportion of the air travels to the end of the blade. 'I'he supportingmeans |00 contact onlya small part of the tubes 91 and 98 and hold thesetubes out of contact with thev remainder of the blade structure sothatthe tubes are substantially insulated :fromk the blade structure and canoperate at high temperatures.

Toward the upstream end of each of the tubes 91 and 98 there is a fuelsprayer |02", both of which are supplied with fuel from a supply pipe|03 that passes down the inside of the blade and communicates with aflexible fuel supply tube |05 (Figure 2) leading to a fuel header |08 inthe rotor hub. This header |06 is at the upper end of a vertical feedpipe |01 that rotates as a unit with the rotor but extends down into alower feed pipe |88 attached to the non-rotatable portions of the rotorhub. This connection provides a rotatable joint in the fuel line. Aflexible tube |09 at the lower end of the pipe |08 permits the pipe |08to move as a unit with the tiltable elements of the rotor. This fuelpipe |08 connects with a fuel supply source, not shown, from which fuelis supplied to the tube |09, pipe |08, and header |08 under somepressure.

The tubes 91 and 98 are made of material, either ceramic or metal, thatcan be heated above the ignition temperature of the fuel with which theburners #are intended to be used. Each of the burners is provided withan electrical ignition device such as a spark plug |05 located downstream from the fuel sprayers |02. When the burners are used, fuel issupplied to the sprayers |02 and the atomized or vaporized fuel from thesprayers travels down the tubes with the current of air that enters theopen end of the tubes around the sprayers |02. This mixture of fuel andair is ignited by the spark plugs |05 and burns within the tubes 91 and98 causing the tubes to beco-me heated to a temperature above theignition temperature of the fuel. Because of the high velocity of theair stream through the rotor blade and through the tubes 91 and 98, theflames would be blown away from the sprayers |02 and satisfactorycombustion of the fuel would not be obtained were it not for the hightemperature of the tubes 91 and 98 after the burners are in fulloperation. The diameter of the opening through each of the burners 91and 93 is so correlated with the velocity of the air stream and the rateof flame propagation through the airfuel mixture that flame ignited fromthe hot walls of the tube, if not otherwise, will traverse the entirecross section of the air-fuel stream and thoroughly burn the fuel beforeit passes from the tubes 91 and 98 and mixes with the other air on itsway to the nozzle 89.

I-Iigher efficiency can be obtained by projecting the reaction jets fromthe nozzle 89 only during the time that the rotor blade of that nozzleis advancing. In order to take advantage of this fact, the nozzle 89 isthen equipped with a slide valve having a yoke ||2 by which the slidevalve can be dra-wn across the nozzle 89 to shut olf the flow ofcompressed gas from the nozzle when the rotor blade is retreating. Theslide valve moves in a guide H5 secured to the nozzle 89.

The operating mechanism for the slide valve includes a lever |18connected to the rotor by a pivot ||9, and moved periodically by aplunger |2| that slides in a solenoid |22. Power to energize thesolenoid |22 is supplied by a conductor |24. This conductor extends downthe blade 35 to a brush |25 (Figure 2) that rides on a commutator |21,and the conducting and insulating sections of the commutator |21 are socorrelated in their angular extent that power is supplied to loperatethe solenoid and close the Valve to shut off the iet whenever the bladechanges from an advancing to a retreating phase of its movement. Theconducting segments of the commutator are insulated from the hub 3|. Aconductor ring |30, mounted on and insulated from the hub 3|, is locatedjust below the commutato-r |21 and supplies power through a brush |32and conductor |33 to the spark plugs or other igniters for the burnersin the rotor blades. There are separate brushes |25 and |32, andseparate conductors |24 and |33 for each of the rotor blades.

The preferred embodiment of the invention has been described but changesand modifications can be made and some features of the invention can beused without others.

I claim as my invention:

1. The method of burning fuel in a sustaining airfoil section throughwhich a stream of air is blown at a maximum velocity of V feet persecond and in which the fuel mixture within the air has a rate of flamepropagation of P feet per second in the air fuel mixture within theairfoil section, the flame propagation rate being substantially lessthan the velocity of the air stream, which method comprises passing aportion of the air stream through an open ended tube extendinglengthwise of the air stream, mixing fuel with the portion of the airstream that flows through the tube by supplying the fuel to said portionof the air stream at a location near the upstream end of the tube, andigniting the air fuel mixture from incandescent surfaces of the tubewall throughout a length of the air-fuel stream which is equal in feetto at least RV/P Where R is the distance of the ignition wall surfacesfrom the longitudinal axis of the air-fuel stream.

2. In the heating of an air stream which passes through a helicopterrotor blade to a jet discharge orifice near the tip end of the blade,and in which a portion of the air stream passes through a combustionchamber open at both ends and extending longitudinally of the rotorblade, and in which another portion of the air stream passes between thecombustion chamber and the rotor blade to prevent excessive heating ofthe rotor blade, the improvement that comprises injecting the fuel intothe air stream in the tube and igniting the air fuel mixture fromincandescent walls of the tube which extend for a distance equal to atleast L feet down stream from the location at which the fuel is mixed`with the air stream, and passing the air fuel mixture through the tubeat a velocity in feet per second not greater than the ratio PL/R, whereP is the rate of flame propagation in the air fuel mixture and R is theinside radius of the tube.

WITOLD BRZOZOWSKI.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,839,880 I-Iyatt Jan. 5, 1932 2,268,464 Seippel Dec. 30, 19412,371,687 Gerhardt Mar. 20, 1945 2,396,068 Youngash Mar. 15, 19462,418,911 Smith Apr. 15, 1947 2,448,561 Way Sept. 7, 1948 2,457,936Stalker Jan. 4, 1949 2,470,184 Pfenninger May 17, 1949 2,477,683 BirmannAug. 2, 1949 2,563,744 Price Aug. 7, 1951 FOREIGN PATENTS Number CountryDate 227,151 `Great Britain Jan. 12, 1925

